Enhancing durability of steam‐cured precast concrete culverts using <scp>SCMs</scp> : A comparative study with delithiated beta spodumene

Abstract Steam curing is commonly used to manufacture precast culverts to accelerate early strength development. This study investigates the effect of supplementary cementitious materials (SCMs) on the permeability properties of steam‐cured precast concrete culverts. The performance of commercially available SCMs, such as Ground granulated blast furnace slag (GGBFS), fly ash (FA), was compared with delithiated beta spodumene (DBS), an emerging, underutilized SCM, which was used as 20% cement replacements by mass. Their effects on concrete were evaluated by sorptivity, volume of permeable voids (VPV), and pressure‐driven water penetration test. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were employed to examine hydration and microstructure. At 90 days, FA and DBS incorporated concrete mixes showed substantial improvements in the fluid transport properties, achieving reductions of over 11% in VPV, 43% in sorptivity, and 33% in water penetration depth when compared to the control, while the GGBFS mix exhibited modest improvements. TGA results confirmed increased calcium silicate hydrate (C‐S‐H) formation and reduced calcium hydroxide (CH), indicating enhanced pozzolanic activity in concrete mixtures where cement was replaced by FA and DBS compared to control concrete. SEM analysis revealed refined pore structures and reduced microcrack connectivity in concrete specimens containing FA and DBS replaced. Both FA and DBS demonstrated comparable, superior performance to the control mixture. These results highlight the potential of DBS as an effective alternative SCM for enhanced long‐term durability of steam‐cured precast culverts, particularly where traditional SCMs like FA are in limited supply.